U3 AOS2 P1 Cellular Signals

Question 1

What is Homeostasis?

Answer 1

The maintenance of a relatively stable internal environment

Question 2

What are the 4 main ways multicellular organisms communicate with each other?

Answer 2

1. Hormones
2. Cytokines
3. Pheromones
4. Neurotransmitters

Question 3

What are the 3 main steps of Cellular Communication?

Answer 3

1. Reception
2. Transduction
3. Cellular Response

Question 4

What are the 3 main ways of signalling?

Answer 4

1. Autocrine
2. Paracrine
3. Endocrine

Question 5

What is Autocrine Signalling?

Answer 5

Signalling which occurs when a cell acts on a signal molecule which it also produced

Question 6

What is an example of Autocrine Signalling?

Answer 6

T lymphocytes releasing Cytokines

Question 7

What is Paracrine Signalling?

Answer 7

Signalling which occurs when a cell acts on a signal molecule that was produced in a different nearby one

Question 8

What is an example of Paracrine Signalling?

Answer 8

Neurotransmitters

Question 9

What is Endocrine Signalling?

Answer 9

Signalling which occurs when a cell acts on a signal molecule that was produced in a different one far away from the receiving one.

Question 10

What is an example of Endocrine Signalling?

Answer 10

Hormones

Question 11

What is an Animal Hormone?

Answer 11

Signal Molecule which is produced in small amounts that have long lasting effects on the body.

Question 12

What do Hormones do?

Answer 12

Regulate growth and metabolic activity

Question 13

How do Hormones travel?

Answer 13

In the bloodstream

Question 14

Where are Animal Hormones produced?

Answer 14

By glands in the Endocrine System

Question 15

What are the 3 main categories of Animal Hormones?

Answer 15

1. Lipid (steroid) hormones
2. Peptide and Protein Hormones
3. Amino Acid Derivatives

Question 16

Which Animal Hormones are HYDROPHOBIC?

Answer 16

Lipid Hormones and Amino Acid Derivatives

Question 17

Which Animal Hormones are HYDROPHILIC?

Answer 17

Peptide and Protein Hormones

Question 18

Whats the difference between Hydrophilic and Hydrophobic Hormones?

Answer 18

Hydrophobic hormones can easily diffuse across the Plasma Membrane due to it’s structure, unlike Hydrophilic ones which get repelled.

Question 19

What is a Plant Hormone?

Answer 19

Signal Molecule which is produced in low concentrations with long lasting effects

Question 20

Where are Plant Hormones produced?

Answer 20

Produced in cells located in different parts of the plant.

Question 21

What are the 5 main categories of Plant Hormones?

Answer 21

1. Auxins
2. Abscisic Acid
3. Cytokinins
4. Ethylene
5. Giberellins

Question 22

Where is Auxin produced and what does it do?

Answer 22

Auxin is produced in the tips of shoots and seeds, and bends the shoot so it grows up towards a light source while causing roots to grow down.

Question 23

Where is Abscisic Acid produced and what does it do?

Answer 23

Abscisic Acid is produced in chloroplasts of leaves and in shoots and causes seed and bud dormancy along with drought tolerance.

Question 24

Where is Cytokinins produced and what does it do?

Answer 24

Cytokinins is produced in roots and developing fruit and causes lateral growth of branches.

Question 25

Where is Ethylene produced and what does it do?

Answer 25

Ethylene is a gas produced by ripened fruit that causes an increase in sugar levels in fruit (ripening), as well as causing them and leaves to drop off the tree.

Question 26

Where is Giberellins produced and what does it do?

Answer 26

Giberellins is produced in roots, shoots and growing leaves and seeds, and causes stem and leaf growth, seed germination and fruit/flower maturation.

Question 27

Outline 2 differences between Plant Hormones and Animal Hormones.

Answer 27

1) One type of plant hormone can produce multiple different responses unlike animal hormones that specific.
2) Many hormones in plants may be required to be present for a specific response to occur, where only one animal hormone is need for a response.

Question 28

How do Neurons communicate with each other?

Answer 28

Through electrical impulses which stimulate the release of chemicals known as Neurotransmitters from vesicles in the pre-synaptic neuron which then move across the synaptic cleft and bind to receptors on the post-synaptic neuron continuing the signal.

Question 29

What is a Synapse?

Answer 29

The gap between Neurons which Neurotransmitters carry the signal across from one Neuron to the next.

Question 30

What is a Neurotransmitter?

Answer 30

Chemical signalling molecule found in Neurons which travel via paracrine signalling.

Question 31

What are the 2 types of Neurotransmitters?

Answer 31

Excitatory Neurotransmitters and Inhibitory Neurotransmitters

Question 32

What are Cytokines?

Answer 32

A group of hydrophilic chemical signalling molecules that mainly used by immune cells to communicate.

Question 33

What do Cytokines do?

Answer 33

They assist the immune system in responding to damage or pathogens, and bind to cells to trigger a response.

Question 34

What are some of the properties of Cytokines?

Answer 34

The receptors which they bind to are always found on the exterior of the Plasma Membrane, as they are hydrophilic and cannot diffuse across it. They also travel via autocrine or paracrine signalling.

Question 35

What are Pheromones?

Answer 35

Chemical signal molecules which are secreted into the environment

Question 36

What do Pheromones do?

Answer 36

Released by one individual that will communicate with and have an affect on a different member of he same species